1. Field of the Invention
This invention relates to a display device for a camera for performing shutter release, film advance and the like by a remote-control operation, and more particularly, to a remote-control signal reception-standby display.
2. Description of the Related Art
The present applicant has proposed a device for releasing a camera mechanism by a remote-control operation in Japanese Patent Provisional Publication No. 118,729/1988 (laid open to public inspection on May 23, 1988). FIG. 2 shows a configuration in which the present invention is used in the context of the above-mentioned proposal.
FIG. 2 shows a control circuit 1 comprising a microcomputer for electrically controlling a camera. An exposure control circuit 2 for controlling a shutter and the like, and a winding circuit 3 for performing film-feeding are controlled by the control circuit 1. A release switch 4 which is turned on by depressing a release button, a self-timer switch 5 which is turned on by depressing a self-timer start button and a remote-control mode switch 6 which is turned on when a remote control signal is input to the control circuit 1, respectively.
A photosensor 8 for sensing a remote-control signal is connected to a remote-control signal receiving circuit 7 for receiving the remote control signal. When the receiving circuit 7 receives the remote-control signal, it sends an output to the control circuit 1 to indicate that the signal has been received.
An LED 9 for displaying that a self-timer is in operation is controlled by the control circuit 1 and is driven by a driving circuit 14. A remote-control signal transmitter 10 transmits the remote-control signal. A switch 11 connected thereto is depressed when the remote-control signal is to be transmitted. A switch 12 sets a signal mode to be transmitted. When the switch 12 is turned on to an M1 side, a first mode 1 signal is transmitted, and when the switch 12 is turned on to an M2 side, a second mode 2 signal is transmitted. A light-emitting device 13 emits a remote-control signal light.
The operation of such a camera having a remote-control function is shown in the flow chart in FIG. 6.
First, when there is no switch operation, and stand-by is not performed so as to use remote control, a loop of steps #1.fwdarw.#2.fwdarw.#3.fwdarw.#1 is formed.
That is, at step #1, it is checked whether or not the release switch 4 is depressed. When it is depressed, the operation proceeds to step 2/38. When it is not depressed, the operation proceeds to step #2 where it is checked whether or not the self-timer switch 5 is depressed. When it is depressed, the operation proceeds to step #6. When it is not depressed, the operation proceeds to step #3, where it is checked whether or not the mode is a remote-control mode. In the case of FIG. 2, when the remote-control mode switch 6 is turned on, the mode is the remote-control mode, and the operation proceeds to step #4. When the remote-control switch 6 is off, the mode is not the remote-control mode, and the operation returns to step #1. Thus, the loop of steps #1.fwdarw.#2.fwdarw.#3.fwdarw.#1 recirculates until there is an input.
When the release switch 4 is depressed, the operation proceeds from step #1 to step #8. At step #8, opening/closing of a shutter is performed by the exposure control circuit 2 to expose the film. The operation then proceeds to step #9, where the film is wound by one frame by the winding circuit 3 to complete preparation for the next photographic operation, and the operation then returns to step #1.
When the self-timer switch 5 is depressed, the operation proceeds from step #2 to step #6. Step #6 consists of a timer operation covering 8 seconds, during which time interval the LED 9 flashes at 2 Hz as a self-timer display by the driving circuit 14. After 8 seconds elapse, the operation proceeds to step #7, which consists of a timer covering 2 seconds, during which time inverval the LED 9 flashes at 8 Hz. The time chart of the operations at steps #6 and #7 is shown in FIG. 4. It is possible to confirm that the self-timer has been started (is in operation) by the flashing of the LED 9 at 2 Hz at step #6, and to know that shutter release is imminent by flashing of the LED at 8 Hz at step #7.
When 2 seconds have elapsed after beginning step #7, the operation proceeds to step #8, where exposure to the film is performed as when the release switch is depressed, and then to step #9, where winding is performed, and returns to step #1.
The foregoing description is an operational example of a case where the remote-control is not selected.
Next is an explanation of a case in which the remote-control mode switch 6 is turned on, and the mode is the remote-control mode.
In the case of the remote-control mode, it is determined at step #3 that the remote-control mode is desired. At step #4, it is checked whether or not the remote-control signal mode 1 has been received. It has not been received, the operation proceeds to #5, where it is checked whether or not the remote-control signal mode 2 has been received. If it has not been received, the operation returns to step #1.
Thus, a loop of steps #1.fwdarw.#2.fwdarw.#3.fwdarw.#4.fwdarw.#5.fwdarw.#1 is formed. When the release switch 4 or the self-timer switch 5 is depressed, shutter release or photographing by the self-timer is performed, respectively, totally in the same manner as in the above-described operation without using the remote-control mode.
Suppose now that the switch 11 of the remote-control signal transmitter 10 is depressed. A remote-control signal of either the mode 1 or mode 2 is then output from the light emitting device 13 depending on the state of the switch 12. This signal is sensed by the photosensor 8, and the remote-control signal receiving circuit 7 outputs to the control circuit 1 that the remote-control signal of either mode 1 or mode 2 has been received. The function for performing a determination between mode 1 and mode 2 may be provided either in the remote-control signal receiving circuit 7 or in the control circuit 1.
In the case of the mode 1 signal, for example, the operation proceeds from step #4 to step #7 in FIG. 6. The steps after step #7 are the same as those after step #7 in the case of the self-timer, wherein the self-timer display flashes for 2 seconds at 8 Hz by the LED 9, and then exposure and winding are performed at steps #8 and #9, respectively. That is, in the remote-control mode 1, when the remote-control signal has been received, shutter release is performed after 2 seconds elapse.
On the other hand, when the remote-control signal of mode 2 has been received, the operation proceeds from step #5 to step #8. Thus, when the remote-control signal of the mode 2 has been received, shutter release is immediately performed.
Now, such a display device for a camera cannot easily confirm whether or not the camera and the remote-control signal receiver are in standby state relative to remote control operation. There is an inconvenience that, in the camera illustrated in FIG. 2, for example, even when the camera is set at a standby state for receiving the remote-control signal by turning on both the switch 6 for setting the remote-control mode and the main switch for switching on the power supply of the entire camera, the user cannot easily confirm whether or not the standby state has been set.
There are also problems that, when the photographer does not notice the fact that the camera is in the standby state capable of receiving the remote-control signal, the film is wasted due to an unintended release by misoperation of the camera caused by mishandling or unintentional sending of a remote-control signal, noise or the like, or electric power is uselessly consumed in the remote-control signal receiving circuit and so consumption of the power supply battery is accelerated.